Daniel Craig had a plan for each day of the week to get into shape to become Bond. 4-5 days of lifting and the other days for rest and a bit of cardio.
Ideally, you'll be able to do 40-60 minutes in a session. That's not always the case, and it is possible to still get in a good workout in less time. Circuits are best for saving time. I've posted a workout plan (the body weight 200) that takes 15 minutes or so. I'd say that's pretty good for beginners. If you're a bit more advanced I think it requires 2 or 3 of those circuits to wear you out. Aside from how many minutes you're putting into a workout session, the other question is how many days a week you're exercising:
Two days a week: If you only have 2 days, you should stick to total body workouts. Hitting your major muscles twice a week can be enough, any less and they'll have too much rest time and have no reason to grow. Circuits are great if you've only got 2 days, but if you're not wanting a fat burning routine and you want to build muscle, pick exercises that work the major muscles and do sets of 8-12 reps with a bit more rest between exercises.
Three days a week: I've done 3 days a week and used total body workouts each of those days and I find that I have enough rest from the off days. You can also do a split routine, where you go upper body/lower body/upper body one week, then go lower/upper/lower the next.
Four days a week: You can incorporate splits here too, going upper/lower/upper/lower on Monday/Tuesday/Thursday/Friday. The exact exercises you do depend on your goals and experience.
Experience: A few considerations to take into account regarding your experience when you make your plan. If you're a beginner, you'll benefit from just about any program, and it's best to keep it simple. High reps, basic exercises, total body workouts. You should be able to recover in 48 hours, so 3 times a week is doable. You can stick with the same routine for 6-10 weeks and still see results.
If you're more advanced, you'll benefit more from heavier weights, lower reps, and more advanced exercises and techniques. Because your working your muscles a bit harder, those muscles will need more rest to recover. Since your body is used to the challenges you're throwing at it, you'll need to vary your programs much more often than a beginner, like every 2 or 3 weeks.
